Re: Redefining an existing Table Schema for Foreign Key Constraint - Question

In article <20294223.post@talk.nabble.com>,
Brian714 <bndang@uci.edu> writes:

> Currently, the database contains thousands of records in the Customers and
> Creditcards tables. I would like to re-define the Customers table to follow
> the following schema:

> Customers Table
> id:integer -- primary key
> first_name:varchar(50)
> last_name:varchar(50)
> cc_id:integer references Creditcards.id
> address:varchar(200)
> email:varchar(50)
> password:varchar(20)

> As you can see, I would like to convert the column that used to be
> "credit_card_number" from the Customers table and turn it into a "cc_id"
> which is an integer that references the column "id" from the table
> Creditcards.

This is the usual 1:n relationship, but I think you got it backwards.
There are two questions to ask:
1. Are there customers with more than one credit card?
2. Are there credit cards owned by more than one customer?